Measurement of the broad-line region size in two bright quasars

Shai Kaspi; Paul S. Smith; Dan Maoz; Hagai Netzer; Buell T. Jannuzi

doi:10.1086/310339

Measurement of the broad-line region size in two bright quasars

Shai Kaspi, Paul S. Smith, Dan Maoz, Hagai Netzer, Buell T. Jannuzi

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48 Scopus citations

Abstract

We present 4 years of spectrophotometric monitoring data for two radio-quiet quasars, PG 0804+762 and PG 0953+414, with typical sampling intervals of several months. Both sources show continuum and emission-line variations. The variations of the Hβ line follow those of the continuum with a time lag, as derived from a cross-correlation analysis, of 93 ± 30 days for PG 0804+762 and 111 ± 55 days for PG 0953+414. This is the first reliable measurement of such a lag in active galactic nuclei with luminosity L > 10⁴⁵ ergs s^-1. The broad-line region (BLR) size that is implied is almost an order of magnitude larger than that measured in several Seyfert 1 galaxies and is consistent with the hypothesis that the BLR size grows as L_0.5.

Original language	English (US)
Pages (from-to)	L75-L78
Journal	Astrophysical Journal
Volume	471
Issue number	2 PART II
DOIs	https://doi.org/10.1086/310339
State	Published - 1996
Externally published	Yes

Keywords

Galaxies: active
Quasars: emission lines

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/310339

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@article{eb7cfce9ab7349fe8da0358638f9bab3,

title = "Measurement of the broad-line region size in two bright quasars",

abstract = "We present 4 years of spectrophotometric monitoring data for two radio-quiet quasars, PG 0804+762 and PG 0953+414, with typical sampling intervals of several months. Both sources show continuum and emission-line variations. The variations of the Hβ line follow those of the continuum with a time lag, as derived from a cross-correlation analysis, of 93 ± 30 days for PG 0804+762 and 111 ± 55 days for PG 0953+414. This is the first reliable measurement of such a lag in active galactic nuclei with luminosity L > 1045 ergs s-1. The broad-line region (BLR) size that is implied is almost an order of magnitude larger than that measured in several Seyfert 1 galaxies and is consistent with the hypothesis that the BLR size grows as L0.5.",

keywords = "Galaxies: active, Quasars: emission lines",

author = "Shai Kaspi and Smith, {Paul S.} and Dan Maoz and Hagai Netzer and Jannuzi, {Buell T.}",

note = "Funding Information: We thank John Dan and the Wise Observatory staff for their expert assistance with the observations. We are grateful to Tal Alexander for illuminating discussions and to the anonymous referee for several constructive comments. Astronomy at the Wise Observatory is supported by grants from the Israel Academy of Science. Monitoring of PG quasars at Steward Observatory is supported by NASA grant NAG 5-1630. B. T. J. acknowledges support from the National Optical Astronomy Observatories, which is operated by AURA, Inc., on behalf of the National Science Foundation.",

year = "1996",

doi = "10.1086/310339",

language = "English (US)",

volume = "471",

pages = "L75--L78",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2 PART II",

}

TY - JOUR

T1 - Measurement of the broad-line region size in two bright quasars

AU - Kaspi, Shai

AU - Smith, Paul S.

AU - Maoz, Dan

AU - Netzer, Hagai

AU - Jannuzi, Buell T.

N1 - Funding Information: We thank John Dan and the Wise Observatory staff for their expert assistance with the observations. We are grateful to Tal Alexander for illuminating discussions and to the anonymous referee for several constructive comments. Astronomy at the Wise Observatory is supported by grants from the Israel Academy of Science. Monitoring of PG quasars at Steward Observatory is supported by NASA grant NAG 5-1630. B. T. J. acknowledges support from the National Optical Astronomy Observatories, which is operated by AURA, Inc., on behalf of the National Science Foundation.

PY - 1996

Y1 - 1996

N2 - We present 4 years of spectrophotometric monitoring data for two radio-quiet quasars, PG 0804+762 and PG 0953+414, with typical sampling intervals of several months. Both sources show continuum and emission-line variations. The variations of the Hβ line follow those of the continuum with a time lag, as derived from a cross-correlation analysis, of 93 ± 30 days for PG 0804+762 and 111 ± 55 days for PG 0953+414. This is the first reliable measurement of such a lag in active galactic nuclei with luminosity L > 1045 ergs s-1. The broad-line region (BLR) size that is implied is almost an order of magnitude larger than that measured in several Seyfert 1 galaxies and is consistent with the hypothesis that the BLR size grows as L0.5.

AB - We present 4 years of spectrophotometric monitoring data for two radio-quiet quasars, PG 0804+762 and PG 0953+414, with typical sampling intervals of several months. Both sources show continuum and emission-line variations. The variations of the Hβ line follow those of the continuum with a time lag, as derived from a cross-correlation analysis, of 93 ± 30 days for PG 0804+762 and 111 ± 55 days for PG 0953+414. This is the first reliable measurement of such a lag in active galactic nuclei with luminosity L > 1045 ergs s-1. The broad-line region (BLR) size that is implied is almost an order of magnitude larger than that measured in several Seyfert 1 galaxies and is consistent with the hypothesis that the BLR size grows as L0.5.

KW - Galaxies: active

KW - Quasars: emission lines

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U2 - 10.1086/310339

DO - 10.1086/310339

M3 - Article

AN - SCOPUS:21444441020

SN - 0004-637X

VL - 471

SP - L75-L78

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART II

ER -

Measurement of the broad-line region size in two bright quasars

Abstract

Keywords

ASJC Scopus subject areas

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